In some VoIP networks, a session border controller (SBC) may be employed for managing signaling and/or media streams. A SBC may anchor media (e.g., a VoIP call) to a service provider network so that the media may be diverted for various reasons (e.g., quality control, diagnostic testing, or the Communications Assistance for Law Enforcement Act (CALEA)). However, a SBC may unnecessarily anchor media between two endpoints (e.g. two telephones) that are in one location (e.g., a building) because of separate signaling realms. For example, a customer may utilize multiple private branch exchanges (PBXs) in a building, where each PBX may be connected to a corresponding enterprise gateway. In this framework, each enterprise gateway may have its own signaling realm which may cause the SBC to anchor the VoIP call to the service provider network. As a result, bandwidth associated with a service provider's network may be unnecessarily wasted.